Test-Tube Yew Promises More of Cancer Drug

The anti-cancer chemical taxol, extracted from the bark of scarce Pacific yew trees, apparently can be produced economically from yew bark cells grown in a test tube, a scientist said Friday.

Taxol has been used successfully to fight ovarian and breast cancer and shows promise in fighting lung cancer and melanoma, doctors say.

But it takes more than 60 pounds of bark from the slow-growing Pacific yew tree to treat a single patient for a year, and many of the trees are found in old-growth forests protected by environmental restrictions.

“The hope is that with a culture system, you could produce taxol like penicillin,” said Michael Shuler, a chemical engineering professor at Cornell University.

Shuler told the American Institute of Chemical Engineers meeting in Miami Beach that his project at Cornell is growing yew cells in various ways. The most successful appears to be a chemical broth.

“We have at least one cell line that we work with that will excrete taxol,” he said after presenting his findings.

The production levels are still not economical, but researchers have several promising paths they believe will grow more taxol, he said.

“We’re talking years,” he cautioned. “Probably a three- to five-year period for the possibility of commercial field production.”

He said that of all the public studies aimed at mass-producing taxol, Cornell’s is the most advanced.

The research is funded by the National Cancer Institute in cooperation with the U.S. Department of Agriculture and several companies, said Shuler. The institute has called taxol the best anti-cancer agent in the last 15 years.

No one has been able to synthesize taxol. Officials of Bristol-Myers Squibb Co., producer of taxol, said in June that they had contracted with an Italian company to derive taxol from needles and twigs of some more plentiful yew species in Europe and Asia.